Ops - didnt read the original post properly.
I havent stayed over night but for a week I would still imagine the parking very cheap. Obviously if you give them a call they will give you a price.
From Bristol you could route through Lyneham to Shoreham and along the coast to SFD or LYD. SFD to just east of L2K is obviously the longer crossing so in a single you might prefer the short crossing. From the FIR, Lille will give you a squawk and you can route direct.